The goal of the proposed research is to develop a powerful assay format that has several advantages over current formats. The specific model is to use Xenopus laevis dermal melanophores in a lawn format for high-throughput screening. The platform design is based on methodology developed to screen bead-based peptide libraries and involves transfer of small volume liquid samples to a melanophore plate in which the traditional liquid medium has been replaced by a gel. Compounds deposited in the gel will diffuse towards the underlying melanophores where active species will elicit a response. This response, a visible 'color change', develops within minutes and will be analyzed by subtractive video imaging. In phase I, a melanophore line stably expressing the human beta-2 adrenergic receptor will be screened against a 640-member, commercially available small molecule library at a density of 384 samples per plate. Known adrenergic agonists in the library will be detected. In addition, we will investigate the potential of the lawn format to provide potency information in the same screening experiment through an analysis of observed signal sizes. These results may open the door for pharmacological profiling during HTS. PROPOSED COMMERCIAL APPLICATION: NOT AVAILABLE